Oxygen therapy is the administration of oxygen as a therapeutic intervention. Oxygen therapy may be used for a variety of interventions in both chronic and acute user care where an increased supply of oxygen to the lungs is needed, such that availability of oxygen to different body tissues is increased. Oxygen therapy may be used in different environment settings including hospital and/or home depending on a user's needs.
In order to provide a user with an oxygen-enriched gas, numerous means of generation and administration have been suggested. A known way to provide a user with an oxygen-enriched gas is via a so-called oxygen separator (or oxygen concentrator). Oxygen separators are commercially available and offered in different sizes and efficiencies as to fulfil distinctive user's needs (e.g.: the Philips SimplyGo). Those oxygen separators are capable of separating oxygen from ambient air (an oxygen comprising gas) and venting a nitrogen-enriched gas into the surrounding of said oxygen concentrator, thereby providing a user with an oxygen-enriched gas. Those known oxygen separators may provide for an “on-demand” or a continuous flow of oxygen-enriched gas.
Most of known oxygen separators (also named oxygen concentrators) separate ambient air (an oxygen comprising gas comprising a mixture of approximately 78% of nitrogen, approximately 21% of oxygen, approximately 0.9% of argon and other gases, such as argon, carbon dioxide, hydrogen, neon, helium) into an oxygen-enriched gas and an oxygen-depleted gas in a cyclic mode of operation. In a producing step of the oxygen-enriched generation cycle, ambient air is pressurized into a separating means, such that nitrogen is retained (for instance adsorbed) in said separating means and oxygen is collected as outflowing “product”. In a purging phase of the oxygen-enriched generation cycle, the separating means is regenerated such that the previously retained nitrogen is released from the separating means and expelled from the oxygen separator into the surrounding atmosphere. To achieve the foregoing, usually two or more separating means comprising suitable selectively adsorbing or absorbing materials (such as a sorbent material). In this configuration, while one separating means is in a step producing oxygen at higher pressure, the other separating means sees its sorbent regenerated with part of the oxygen outflow produced by the first device flowing at a lower pressure. After a certain time some valves are switched and both separating means change their role.
A portable oxygen concentrator is known from U.S. Pat. No. 7,402,193. This document discloses a pair of sieve beds having first and second ends, a gas compressor for delivering air to the first ends of the sieve beds, a reservoir communicating with the second ends of the sieve beds, and an air manifold attached to the first ends of the sieve beds. The air manifold includes passages therein communicating with the gas compressor and the first ends of the sieve beds. A set of valves is coupled to the air manifold, and a controller is coupled to the valves for selectively orifice and closing the valves to alternately charge and purge the sieve beds to deliver concentrated oxygen into the reservoir. An oxygen delivery manifold communicates with the second ends of the sieve beds for delivering oxygen from the reservoir to a user. Pressure sensors may be provided in the reservoir and/or delivery line for controlling operation of the controller.
It is a drawback of known oxygen separators, especially portable oxygen separators, that they require a significant amount of energy to purge (or clean) the separating means from the sorbed component(s) during the purging phase of the oxygen-enriched generation cycle. The foregoing drawback leads to bigger power sources means (such as a battery) which are bulky, heavy, and volume demanding thereby limiting the portability of oxygen separators.
US 2004/0050255 discloses an oxygen concentrator which uses two cylinders cyclically in an oxygen generation mode and a back-flush mode. AU 469 601 discloses a gas separation system, for example for separating oxygen and nitrogen. It includes a nitrogen pre-purging and nitrogen purging stage.